1. Field of the Invention
The present invention relates to a wire conductor for a harness, which is applicable to a wire harness for an automobile, for example.
2. Description of the Background Art
With recent improvement of performance, an automobile is wired in a number of portions such as those of various control circuits, with strong requirement for reliability. On the other hand, a lightweight automobile is increasingly required in view of energy saving etc.
In general, a wire conductor for wiring an automobile is mainly prepared from a stranded wire which is obtained by braiding annealed copper wires defined under JIS C 3102 or those plated with tin. Such a stranded wire is concentrically coated with an insulating material such as vinyl chloride, bridged vinyl or bridged polyethylene, to form a wire.
In automobile wiring circuits, the rate of signal current circuits for control etc., in particular, is increased in recent years. A wire for such circuits is formed by a conductor whose diameter is in excess of an electrically required level for maintaining mechanical strength, in spite of sufficient current carrying capacity.
In order to reduce the weight of such a wire, an attempt has been made to prepare its conductor from aluminum (including alloy).
In general, however, aluminum is so inferior in strength that it is necessary to increase the outer diameter of the conductor or the number of stranded wires, in order to attain sufficient strength. Consequently, the amount of the insulating material is increased to require a large wiring space. Thus, the weight of the wire cannot be sufficiently reduced and the cost for the insulating material is increased.